[libvirt-users] bad IO on VM
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I have to create some VM. I using KVM for it, manage by libvirtd. The problem of my is that the IO is very bad. I'm nut sure, but I using currently vmdk. Could this be the problem? My settings for the VM is: vitrio driver vmdk no cache It's so bad that the Oracle DB can't work efficient. http://pastebin.com/raw.php?i=sDyvcJmB so far akendo -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJPM5NGAAoJEARqOhiQNM7ZQKMIAIVo9+SYmSrJAIooB0xObSEz ERmMANdkaA7tLGBWaSvKTh5Gg0d3NdP9P1aCIS38OXBBKxqy2NRcksgMikJmlaVp DitLHsSKKLNpBZpGe9xBvqrNCbJVdFLmWIjYk+WEBWXlxHFYob9FuSdejQ53JKKI mfLbcfhWb/6mEfcgkWVAWh9PumuRKZ8YLwWOfj/qJhkhnJOfsusai8Ns+TfMpO7s M72d2RYknpyXiNEJSwUIDlEl0OHqStG3T4+Tpx8Wmoqfs+cm4Hklca1GFGV/Wao2 aPYdkLYvMamAMyN8tB2I0c9MXXUQ8mxgruJReHM9NUYoX4iIwIazElPcZBp4FWI= =MDJL -----END PGP SIGNATURE-----
On Thu, Feb 09, 2012 at 10:35:02AM +0100, Akendo wrote:
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I have to create some VM. I using KVM for it, manage by libvirtd. The problem of my is that the IO is very bad. I'm nut sure, but I using currently vmdk. Could this be the problem?
I think that is a very likely suspect. The only drivers in QEMU that have had any serious performance tuning are QCow2 and raw. The vmdk driver is not really actively maintained beyond bug fixing. I'd strongly recommend you try just 'raw' file formats instead for maximum performance, and make sure you use 'cache=none' for the disks too. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
Am 09.02.2012 15:01, schrieb Daniel P. Berrange:
On Thu, Feb 09, 2012 at 10:35:02AM +0100, Akendo wrote:
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I have to create some VM. I using KVM for it, manage by libvirtd. The problem of my is that the IO is very bad. I'm nut sure, but I using currently vmdk. Could this be the problem?
I think that is a very likely suspect. The only drivers in QEMU that have had any serious performance tuning are QCow2 and raw. The vmdk driver is not really actively maintained beyond bug fixing. I'd strongly recommend you try just 'raw' file formats instead for maximum performance, and make sure you use 'cache=none' for the disks too.
Let me repeat my question from the other thread here: I wasn't able to set "cache=none", the libvirt(?) complained. 0.9.8, btw. What might be the reason?
participants (3)
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Akendo -
Daniel P. Berrange -
Stefan G. Weichinger